HR 8191, a yellow-white giant star in Equuleus
HR 8191 is a yellow-white giant star in the constellation Equuleus. At 374 light years away, it shines at an apparent visual magnitude of 6.32.
HR 8191 (HIP 105695)
HR 8191 is a yellow-white giant star in the constellation Equuleus. At 374 light years away, it shines at an apparent visual magnitude of 6.32. It is moving through the Galaxy at a speed of 54.1 km/s relative to the Sun.
Sky position: RA 21h 24.4m, Dec +10° 10.5'
Common designations: HR 8191, HD 203842, Gaia DR3 1745193788169506432, HIP 105695
HR 8191 has the spectral type F5III. F-type stars are yellow-white stars of about 6,000 to 7,500 K, slightly hotter and more massive than the Sun. Their hydrogen lines are weaker than in A stars and metal lines become prominent. Its luminosity class III marks it as a giant: an evolved star that has left the main sequence and swollen to many times its original size.
How to find HR 8191 in the sky
HR 8191 lies in Equuleus. With a declination of +10° 10.5', it is visible from the entire Northern Hemisphere and from the Southern Hemisphere down to about latitude 80° S. It is just beyond naked-eye visibility; binoculars will show it easily. It is highest in the sky at local midnight around September, which makes the weeks around that month the best time to observe it.
Tabulated data for HR 8191
Astrometry and spectroscopy
| Right Ascension (J2000) | 321.10234884° (21h 24.4m) |
| Declination (J2000) | 10.17422155° (+10° 10.5') |
| Galactic Longitude | 62.30014816° |
| Galactic Latitude | -27.49625376° |
| Proper motion RA | 74.58 mas/yr |
| Proper motion Dec | 25.11 mas/yr |
| Parallax | 8.72 ± 0.18 mas |
| Spectral Type | F5III |
| Radial Velocity | -33.20 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 6.79 | 1.50 |
| V | 6.32 | 1.02 |
| J | 5.44 | 0.14 |
| H | 5.26 | -0.03 |
| K | 5.17 | -0.12 |
Colour index B-V: +0.47
Derivations
- Heliocentric distance: 114.62 pc (374 light years) (2.0% margin of error)
- Absolute visual magnitude: 1.02
- Transverse velocity: 42.8 km/s
- Space velocity relative to the Sun: 54.1 km/s
- Galactic position (X, Y, Z): 47.3 pc, 90.0 pc, -52.9 pc
- Galactic velocity (U, V, W): -50.4 km/s, -19.1 km/s, -5.5 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.